Corner lock fibreboard container



March 24, 1964 R, GQETZ 3,126,142

CORNER LOCK FIBREBOARD CONTAINER Filed July 5, 1962 will. 22 29o. Il,3?.;2 q2 "H3/y, 29 Il V3 i1" B3 n A g 2' H L I l: 33 i Se w I M E lH||V^ 2J` Y W1 1 E E 'u Il i u MNHN' MMM Il E I: E Il I .IN1 l l i l :I3 3e I l V l .iik 56 I .\MW L; 2 l" s1l` 39 2 3 22 ,I 25%@ :vsq sa g`||||I"' |||.'|l"- l ,LLMHHHUlll 2 "QQ Fig. 1.

INVENTOR. ROBERT L. GoETz YM WMMSWXM wah/d United States Patent3,126,142 CORNER LOCK FIBREBOARD CONTAINER Robert L. Goetz, Dallas,Tex., assignor to Inland Coni tainer Corporation, Indianapolis, Ind., acorporation of Indiana Filed July 5, 1962, Ser. No. 207,646 1 Claim.(Cl. 229-36) This invention relates generally to containers ofthe typecustomarily made of corrugated or uncorrugated fibreboard andinparticular vto a carton vor' container formed from a die cut sheetwhich when closed forms self-locking corner posts.

In the past corner` reinforced containers have been designed whereincornerlocking flaps, formed at vthe junction ofthe end panels .andsidepanel. of the container are folded diagonallyuupon themselves. Suchstructure is illustrated in AndrewsPatent 2,713,962. While such diagonalfold corner reinforcement stabilizes the corner structure and canaccommodate locking tabs extending from the top panel, it does not addto the stacking strength of the carton. Such stacking strength is ofconsiderable importance in applications where a relatively light weightcarton is utilized with contents which cannot survive any substantialcompressive load. An example of such carton applications is thepackaging of bakery goods and the like.

The structure of the present invention provides a corner fold structurewhich not only stabilizes and reinforces the carton corners but alsoreinforces the carton to greatly increase its stacking strength. Thecorner locks are formed by providing an L-shaped cut and a diagonalscore line in locking aps formed at the junctions of the end and sidepanels. Matching tabs are also formed to extend sidewardly from the toppanel and when the locking flaps are folded upon themselves, the tabsare received within the fold providing a lock or retention of the toppanel in overlying position with relation to the base panel. Thearrangement is such that the carton may be reused.

The primary object of the present invention is to provide a cartonformed from a die cut sheet and designed so that when folded and closed,the carton is provided with self-locking corner posts, the corner postsserving to add additional strength to the carton as well as ease inclosing, this being accomplished without the use of tape, stitching orglue.

These and other objects will become apparent as the description proceedswith reference to the accompanying drawings in which:

FIG. l is a top plan view of a die cut sheet from which the container ofthe present invention may be fabricated.

FIG. 2 is a perspective view of the container after it has been foldedor seteup but before the top panel has been lowered into closedposition.

FIG. 3 is a fragmentary perspective view illustrating the position ofthe corner components as the top panel is moved into closed position.

Referring initially to FIG. l, the blank from which the carton is formedhas a generally rectangular overall configuration. The blank istransversely scored at 10, 11 and 12 to provide a top panel 13, a rear,side panel 14, a base panel 16 and a front, side panel 17. A score line18 crossing the top panel 13 defines an extending flange 19. The liange19 may be omitted from the structure or may be formed integrally withthe outer margin of the front panel 17, the actual presence of thefiange 19 and its location forming no part of the present invention. Theside marginal areas of the top panel 13 are scored at 21 and cut alongthe line 22 to provide sidewardly extending tabs 23. The score lines 21form the lines of junction between ice 2 theV tabs 23 and the top panel13-.and the cut 22 has a configurationsuch that the tabs 23 have amarginal portion 24 which is inclined with relation `to the line ofjunction 21 with the top panel.

The longitudinal cuts` 26 and 27 define side locking fiapsZS and 29respectively, the aps 28 and t29 having notches 28a and 29a formedtherein which are adapted to interfit in setting up the container ,aswill subsequently be described. The base panel 16 is scoredat 31 and 32to define end panels 33, the junction between the end panels and thelocking liapsy 23 and 29 being defined byA score lines34 which are ineffect extensions of the score line11.

Transverse score lines36 extend across the front panel 17 and aresubstantiallyaligned with the junction ofthe end panels33 and the basepanel l16 as defined by the score lines 31 and 32. An L-shapedvcut isformed in each of the end panels, one leg 37 of the cut beingsubstantially aligned with the Yjunction ofthe front panel 17 and thebase panel 16 as defined by the score line 12. The cut terminates shortof the outer margin of the end panel and further score lines 38 extendfrom the extremity of the leg 37 of the cut to the outer margin of theend panels. The transverse score lines 36, the further score lines 38and the leg 37 of the L-shaped cut define generally rectangular lockingaps 39. Diagonal score lines 41 extend from the extremity of the otherleg 42 of the L-shaped cuts to the adjacent corner of the locking fiaps39. The score lines 41 are shown in FIG. 1 as double lines, however, itwill be understood that these might be of various spacing or might be a`single line, all such alternatives being included by reference hereinto the score lines 41.

Referring to FIGS. 2 and 3, the container may be set up by folding theend and side panels along the proper score lines into positions normalto the plane of the base panel 16. The side locking fiaps 28 and 29 maybe folded inwardly along the score lines 34 and locked by interfittingthe notches 28a and 29a as indicated in FIG. 2. The tabs 23 are foldedsidewardly along score lines 21 so as to extend generally normal to theplane of the top panel 13.

The corner structure is formed by folding the locking fiaps 39 uponthemselves along the transverse score lines 36, the score lines 3S andthe diagonal score lines 41, as indicated in FIG. 2, so that the lockingflaps 39 overlie the adjacent end panels 33. The locking flaps areretained in this folded condition by insertion of the tabs 23 asindicated in FIG. 3. As there shown, in closing the top panel 13 intospaced overlying relation with the base panel 16 the tabs 23 areinserted between the locking liaps 39 and the adjacent face of the endpanels 33 so that both the tabs 23 and the locking fiaps 39 overlie theadjacent faces of the end panels 33. Although the tab 23 is shown inintermediate position in FIG. 3, it will be understood that when seatedthe inclined margin 24 of the tab 23 will be seated against the inclinedscored area 41 and will thereby retain the corner structure in foldedcondition.

From the foregoing it will be evident that the structure of the presentinvention provides a relatively light weight carton, die cut from a`single blank, and having a corner lock structure which providessubstantial reinforcement of the container for resistance to compressivestress such as occurs in stacking of the containers. The assembly of thecarton is such that it may be opened and reclosed repeatedly withoutcausing visible deformation or deterioration of the carton structure.

While the invention has been disclosed and described in some detail inthe drawings and foregoing description, they are to be considered asillustrative and not restrictive in character, as other modificationsmay readily suggest themselves to persons skilled in this art and withinthe broad `scope of the invention, reference being had to the appendedclaim.

The invention claimed is:

A reinforced corner lock carton including a top panel adapted to beclosed in spaced overlying relation to a base panel, tabs extendingoutwardly from each side margin of said top panel and adapted to befolded along their lines of junction with the top panel into planesnormal to the plane of said top panel, said tabs having a generallyrectangular shape the free edge of which is aligned with said basepanel, end panels extending outwardly from each side margin of said basepanel, a front panel extending outwardly from one end margin of saidbase panel, said end and front panels being adapted for folding intoplanes normal to the plane of said base panel, a transverse score lineextending across said front panel adjacent each of its ends andsubstantially aligned with the junction of said end panels and basepanel, an L-shaped cut formed in each of said end panels, one leg ofsaid cut being substantially aligned with the junction of said front andbase panels and terminating short of the outer margin of said endpanels, the other leg of said cut extending normal to said one leg andterminating short of the outer margin of said front panel, further scorelines extending from the extremity of said one leg of said cut to theouter margin of said end panels, said transverse score lines, saidfurther score lines and said one leg of said cut dening locking flaps,and a diagonal score line extending from the extremity of said other legof said cuts to the adjacent corner of said locking aps, whereby whensaid end panels and front panel are folded normal to said base panelsaid locking flaps may be folded upon themselves along said transversescore lines, said further score lines and said diagonal score lines toprovide a generally rectangular configuration for said locking flaps anddisposing them in overlying relation to the adjacent end panels.

References Cited in the le of this patent UNTTED STATES PATENTS1,111,552 Allers Sept. 22, 1914 1,544,311 Gaffenberger June 30, 19251,985,778 Himes Dec. 25, 1934 2,311,403 Lighter Feb. 16, 1943 2,354,600Kretchmer July 25, 1944

